When light rain descended on the Spa-Francorchamps circuit just before qualifying, it was as if drops of petrol had suddenly fallen on a faltering fire.

There has been a dullness about the buildup to Sunday's Belgian Grand Prix that tempted many to seek distractions from the vroom-vroom business – naming six famous Belgians has been a popular one.

But the wet conditions on Saturday brought a frantic urgency to the pit wall and it was, ultimately, Lewis Hamilton who prevailed to win his fourth consecutive pole position; it is the eighth time in nine races that Mercedes have been fastest in qualifying.

With more rain forecast for Sunday, the race is expected to be anything but dull on this magnificent track, though another victory for Sebastian Vettel, and a hardening of his world championship lead, could provoke a return to the old torpor.

The Red Bulls had been impressively fast in the three practice sessions and, until Hamilton received his sprinkled blessing, the expectation was that they would dominate proceedings.

It was a good day for the Brits all round, with all four of them reaching Q2 for the first time this season, and there will be three of them in the front six on Sunday afternoon.

Paul di Resta, the only man to start Q3 on intermediates, posted an early time that looked likely to win him his first pole as conditions deteriorated. But when he pitted, the rain did the same thing and the surface dried, and the Scot was ambushed by the four cars from Mercedes and Red Bull.

Nico Rosberg was the first to topple the Scot, before Red Bull, and finally Hamilton, made their late marks.

Hamilton, who won here in 2010, had not been very happy with his car all week and almost missed the Q2 cut for the top-10 shootout. He said afterwards: "It was a good job by the team. I was surprised when I came across line. I went wide in Turn One and my dashboard told me I was three seconds down, and then it was four seconds and then six, so I didn't know what was going on, but I kept pushing. It's a blessing I am up here. Generally I feel comfortable in changing conditions. I can find the limit and I pushed through the middle sector and really caned it."

Hamilton admitted that he was not confident before qualifying. "I haven't had a good feeling all weekend," he said. "I'm not 100% confident we have the fastest package in the dry, but, in these conditions, it's more of a lottery and the driver can make more of a difference.

"Our radar has forecast it's going to rain tomorrow, so it's going to be a tricky race. Trying to choose the right tyre, tyre management and pit stops will be key tomorrow."

Hamilton is fourth in the championship, 10 and nine points behind Kimi Raikkonen and Fernando Alonso respectively, but a hefty 48 adrift of Vettel. His old McLaren team-mate, Jenson Button, said on Saturday night: "It's definitely not over yet. If Lewis wins this race and Seb finishes fourth, that is a lot of points, almost 30% of the gap.

"Seb does has a big lead, but if another team is suddenly competitive, which I think they [Mercedes] proved in the last race, and both drivers are doing a good job, that is a lot of points they could take off him. It is going to be exciting with three different teams being quick at different races."

Button had his own reasons to be pleased with the afternoon. He will start sixth on Sunday, his best effort in what has been a bitterly disappointing season for McLaren. "We deserve our position today as we were very competitive," he added.

Di Resta has to make do with fifth, equalling his performance in Bahrain in April. He said: "I thought the rain was going to stay. It was quite a ballsy decision by myself. I saw umbrellas coming up, so I made the right choice.

"I think it was the right time, but our car is not that quick in the wet. It was unfortunate, but P5 is not so bad. In the dry, we're looking good for the race. If it's wet, I'd be a bit more nervous."

It was another desperately disappointing qualifying session for Ferrari, with Fernando Alonso ninth, one place ahead of team-mate Felipe Massa.

Hamilton, though, is becoming something of a one-lap wonder. Seventh in the all-time list of pole winners, he now has 31 and is just two behind the great names of Alain Prost and Jim Clark.

Like Clark and his contemporary Jackie Stewart, Hamilton is also considering other forms of car racing. "I think that would be really cool. I want to go out and do a Nascar race," he said. Hamilton is always capable of saying things that will make Mercedes nervous. But he's also capable of great things, and on Saturday his employers were beaming.